Spin Drift & Coriolis (Long-Range)
Simplified reference estimate for two very-long-range effects. Full solvers (Kestrel, Applied Ballistics) model these more completely.
How this works
Spin drift happens because a spinning bullet's nose very slightly tracks the direction of its own spin as it flies — a right-hand-twist barrel drifts bullets slightly right, regardless of wind. The Litz approximation used here is a widely published simplified formula that estimates this from the bullet's stability factor and time of flight, without needing a full 6-degree-of-freedom simulation.
Coriolis: real, but tiny at hunting ranges
Coriolis deflection comes from the earth rotating underneath a bullet that's in the air long enough for that rotation to matter — it depends on latitude and which direction you're shooting. Both effects genuinely matter to extreme long-range and competition shooters working at 1,000+ yards; full solvers like Kestrel or Applied Ballistics model them with far more precision than this simplified reference.
Frequently asked questions
Do I need to worry about these at typical hunting ranges?
Not usually — both effects are real but tend to amount to well under an inch at ranges under 500 yards, where wind and range-estimation error dominate far more. They matter most for extreme long-range and competition shooting.
Which direction does spin drift push the bullet?
It always drifts in the direction of the bullet's spin — a standard right-hand-twist barrel drifts bullets slightly to the right, regardless of wind conditions.
Is Coriolis the same everywhere on Earth?
No — it depends on latitude and the direction of the shot, which is why both are required inputs. It's strongest at the poles and effectively zero at the equator for a shot fired due north or south.
Explore the whole Calcs family here.
Not happy with our calculations or how it works? Let us know.
Have a suggestion for a calculator you don't see here? Let us know.
All HuntersCalcs tools
Rifle & Scope
Ballistic Coefficient Estimator Bullet Drop / Trajectory Calculator Barrel-Length Velocity Loss (Estimate) BC Truing from Chronograph Cost per Shot / Cost per Hunt Density Altitude Calculator Scope / Binocular Exit Pupil, FOV & Twilight Factor Maximum Point-Blank Range Mil-Dot / MOA Range Estimator MOA / Mil Calculator Muzzle / Downrange Energy & Momentum Free Recoil Energy & Velocity Sectional Density Calculator Sight-In / Zero Correction Spin Drift & Coriolis (Long-Range) Time of Flight & Moving-Game Lead Twist Rate & Bullet Stability Uphill / Downhill Shot Correction Wind Drift CalculatorMuzzleloader
Muzzleloader Ballistics Muzzleloader Powder: Volume, Shots per Pound & Cost Patched Round Ball: Weight, BC & TwistShotgun
Pellet Energy by Shot Size & Range Crossing-Bird Lead Pellet Count & Pattern Density Slug DropArchery & Crossbow
Arrow Drop, Sight Pin Gaps & Yardage Tape Arrow FOC (Front of Center) Arrow Kinetic Energy & Momentum Arrow Speed Estimator Arrow Spine — General Starting Point Total Arrow Weight & GPP Holding Weight from Let-Off Broadhead Penetration Reference: Energy vs. Momentum Crossbow Bolt Drop with Multi-Reticle Scope Draw Length Calculator Treestand / Angle-Shot Horizontal DistanceReloading
Case Capacity from Water Weight Seating Depth off the Lands (CBTO) Chronograph ES / SD Statistics Load Density / Case Fill % Powder Burn-Rate Reference Reloading Cost per Round & Break-Even Load Data Finder Rounds per Pound of PowderDraw Odds
Tag Draw Odds Estimator (Pilot)Land & Herd
Food Plot Seed, Lime & Fertilizer Mix Hunting Lease Cost per Acre / per Hunter Trail Camera Population Estimate (Jacobson Method)Meat Processing
Cost per Pound of Venison Cure & Salt Calculator Freezer Space Needed per Deer Jerky / Sausage Seasoning Scaler Taxidermy Cost Estimator Venison / Fat Blend Ratio (Pearson Square) Venison Cut Yield CalculatorNo calculators match your search.